The MA Wetlands Protection Act and Regulations and local Wetlands Bylaw include a number of different types of wetlands, and wetland-related areas called "Resource Areas". These include rivers and streams ("perennial" if they run year round, and "intermittent" if they dry up seasonally); lakes and ponds; the vegetated wet areas bordering rivers, streams, lakes or ponds ("bordering vegetated wetlands"); the 100-year floodplain along rivers and streams; and isolated areas that flood seasonally, such as vernal pools. The first 200 feet from the edge of a perennial stream are regulated as "riverfront area". The first 100 feet from a vegetated wetland or stream bank are regulated as "buffer zone".
Most people can recognize a marsh with cattails and standing water as a wetland, but many wetlands are harder for the average person to recognize. By law, the edge of vegetated wetlands is determined by looking at the species of plants that grow there, the soils, and evidence of hydrology. Certain plant species are adapted to grow in wet areas. Soils show if the area has water near the surface at least part of the year. Evidence of hydrology includes ponding, sphagnum moss, flood water lines and debris, and physical adaptations made by plants to wet growing conditions.